function step1(){
    return new Promise((resolve,reject)=>{
        setTimeout(()=>{
            console.log("step1执行");
            let step1Data={
                myname:"limin",
            }
            resolve(step1Data)
        },4000)
    })
}
function step2(input){
    console.log(input)
    return new Promise((resolve,reject)=>{
        setTimeout(()=>{
            console.log("step2执行");
            let step2Data={
                //myname:input.myname,
                myname:input.myname,
                myage:30,
            }
            resolve(step2Data)
        },2000)
    })
}
function step3(input){
    console.log(input);
    return new Promise((resolve,reject)=>{
        setTimeout(()=>{
            console.log("step3执行");
            let step3Data={
                myname:input.myname,
                myage:input.myage,
                mylove:"xiongda",
            }
            console.log(step3Data)
        },4000)
    })
}
// step1()
// .then((data)=>{ return step2(data)})
// .then((res)=>{return step3(res)})

step1().then(step2).then(step3)